1. Field of the Invention
This invention relates to chemically sensitized photographic silver halide emulsions and to photographic elements comprising a support having a light-sensitive layer coated from said emulsions. One aspect of this invention relates to sensitizing negative-working silver halide emulsions with at least one macrocyclic polyamine or a chelate with a metal taken from the group consisting of iron, nickel, copper, rhodium and thallium. Another aspect of this invention relates to sensitizing a direct positive, silver halide emulsion with at least one macrocyclic polyamine or metal chelate thereof. The photographic emulsion sensitization according to this invention is generally applicable to negative-working and positive-working silver halide developing out emulsions.
2. Description of the Prior Art
Chemical sensitizers, as distinguished from optical sensitizers, are frequently used to enhance the sensitivity of silver halide emulsions. Compounds known to be useful as chemical sensitizers include, for example, the polyoxyalkylene compounds, sulfur compounds, and salts of noble metals, e.g., gold, platinum, etc.
This invention relates to adding macrocyclic polyamines to silver halide emulsions as chemical sensitizers. Many macrocyclic amines of the invention are known. These compounds and methods of preparing them and their salts and metal chelates are described in the following prior art and literature references, which are incorporated herein by reference: N. F. Curtis, Coord. chem. Rev. 3, 3 (1968), D. C. Olson and J. Vasilevskis, Inorg. Chem. 8, 1611 (1969), L. G. Warnes et al, J. Am. Chem. Soc., 90:25, 6938 (1968), N. F. Curtis et al, J. Chem. Soc., 1015 (1966), L. G. Warner and D. H. Busch, J. Am. Chem. Soc., 91:15, 4092 (1969), M. M. Blight and N. F. Curtis, J. Chem. Soc. 3, 3016 (1962), D. C. Olson and J. Vasilevskis, Inorg. Chem. 10, 463 (1971), N. F. Curtis, J. Chem. Soc., 2644 (1964), M. O. Kestner and A. L. Allred, J. Am. Chem. Soc., 94:20, 7189 (1972), B. Bosnick et al, Inorg. Chem. 4, 1102 (1965), G. A. Kalligeros and E. L. Bluin, Inorg. Chem. 11, 1145 (1972), H. Stetter and K. H. Mayer, Chem. Ber., 94, 1410 (1961), J. P. Collman and P. W. Schneider, Inorg. Chem., 5, 1380 (1966); and U.S. patent application Docket No. CR-7505, filed Oct. 4, 1973 by J. E. Richman. While preparation of macrocyclic amines is described in these references, silver halide emulsions containing these compounds have not been known.